"Listen At It" is a tool to help you hear what your phone's camera is looking at. When you touch the screen (double tap if using VoiceOver), the app will take a photo using your iPhone's back camera, then you can move your fingers around to hear sound representing color of the point of touch. The frequency of the whistle represent color, lower to higher pitch means from red to yellow to blue then to velvet. More noise means it's brighter. By rubbing finger back and forth, you may be able to identify what you are Listening At.